In today’s world, security is one of the most important needs for every home, office, shop, or private space. Traditional key-based door locks can be easily lost, duplicated, or even broken. To solve this problem, smart automation and AI-based technology bring a modern solution — a Smart Door Lock System using ESP32, Face Recognition Camera (ESP32-CAM), and IoT (Blynk App / IFTTT / Firebase / Google Assistant).

This project allows you to:

✔ Unlock your door using your Face (AI Face Recognition)
✔ Control the door from a mobile app (Blynk IoT / Google Assistant / Alexa)
✔ Automatically notify the owner via mobile if an unknown person tries to access the door
✔ Open/Close lock using keypad, RFID card, fingerprint, or voice command (optional)
✔ Store entry logs and monitor door status in real-time on your phone

It is a perfect DIY project for students, engineers, IoT developers, security lovers, and smart home enthusiasts.

🎯 Project Goals

Goal	Description
✅ Smart & Keyless	Unlock door without using any physical key
✅ AI-Powered Security	ESP32-CAM identifies the face and only allows authorized people
✅ Mobile App Control	Lock/unlock via Blynk or Google Assistant from anywhere
✅ Real-Time Alerts	Sends push notifications if unauthorized access is detected
✅ Easy Hardware	Uses low-cost modules like ESP32, relay, servo/solenoid lock
✅ Expandable	Can add fingerprint, keypad, RFID, GSM module in future

🤖 How This System Works (Simple Explanation)

Face Detection/Recognition:
ESP32-CAM scans the face using the built-in OV2640 camera and compares it with saved authorized face data.
ESP32 Wi-Fi Module:
If the face is authenticated, the ESP32 sends a signal to the servo motor or electronic door lock.
Mobile App (Blynk/IFTTT):
You can also open or close the lock manually using your smartphone.
Notification System:
If someone unknown tries to open the door, the system captures their photo and sends it to your phone via email or Blynk alert.
Door Lock Mechanism:
A servo motor / solenoid lock is connected to the ESP32 which physically locks/unlocks the door.

📦 Applications of This Project

✔ Smart Homes
✔ Office & Private Cabins
✔ Hostel, PG, Apartment Security
✔ Lab/Server Room Access Control
✔ Hotels & AirBnB Smart Entry Systems
✔ School & College Entrance Gates

💡 Why Smart Door Lock is Better than Traditional Locks?

Traditional Door Lock	Smart Door Lock (This Project)
Uses key only	Keyless – Face, App, Voice control
Keys can be lost or copied	Encrypted & secured access
No remote access	Open door from anywhere via Wi-Fi
No alert system	Sends alerts if unauthorized access
Manual operation only	Fully automatic and smart

⚙️ Part 2 – Components & Working of AI + IoT Smart Door Lock System

In this section, we will understand all the components used in this project, their purpose, and how they work together to make a fully smart security system. Every component has been selected based on performance, cost-effectiveness, and compatibility with IoT and AI features.

🧾 🔹 Required Components List

Component Name	Quantity	Purpose
ESP32 / ESP32 Dev Board	1	Main Wi-Fi microcontroller to control the system
ESP32-CAM (AI Camera Module)	1	For face detection and recognition
OV2640 Camera	Inbuilt	Captures face images
Servo Motor / Solenoid Lock	1	For physically locking/unlocking the door
Relay Module (5V/3.3V)	1	To control the door lock or electromagnetic latch
Power Supply (5V/2A or 12V with buck converter)	1	Provides stable power to ESP32, camera & lock
Push Button / Doorbell Switch (optional)	1	Manual door unlocking/doorbell feature
Breadboard / PCB / Wires	–	For circuit connections
Smartphone with Blynk App / IFTTT / Google Home	1	To control and monitor door remotely
Micro SD Card (optional)	1	To store captured images or logs
Jumper Wires (Male/Female)	–	For connection between modules

🧠 🔹 How Each Component Works

✅ 1. ESP32 Development Board

Acts as the brain of the system.
Connects to Wi-Fi and Blynk/MQTT/IFTTT cloud.
Controls relay/servo motor based on face detection or mobile app command.

✅ 2. ESP32-CAM (Face Recognition Module)

Comes with OV2640 camera sensor which captures live face images.
Uses inbuilt AI-based face detection algorithm.
Can store registered faces and compare them in real-time.

✅ 3. Servo Motor / Electronic Lock

This is the physical lock/unlock mechanism.
When an authorized face is detected or unlock command is received, the servo rotates and opens the latch.
Compact and consumes very low power.

✅ 4. Relay Module

Works like an electronic switch.
Used when controlling a magnetic/solenoid lock instead of servo.
Can handle high voltage locks safely using ESP32 signals.

✅ 5. Power Supply

ESP32 and servo/lock require a stable 5V or 12V supply.
For safety, use a 5V 2A adapter or 12V adapter + buck converter (to 5V).

✅ 6. Mobile App (Blynk / IFTTT / Google Assistant)

Allows door control from anywhere in the world via the internet.
You receive real-time notifications or emails when someone tries to unlock the door.
Can integrate voice commands like:
“Hey Google, unlock the door” ✅

🔄 🔹 Working Principle (Step-by-Step Explanation)

Person stands in front of door → Camera scans face
ESP32-CAM detects if the face is known or unknown
✅ If Authorized Face → Lock opens automatically
❌ If Unknown Person → Alert sent to owner (photo + notification)
You can also:
- Unlock door manually from Blynk App / Google Assistant
- Use push button or RFID/Fingerprint (optional)
Door automatically locks after a delay for safety.

📊 🔹 System Flowchart Overview

[Start]
   ↓
Camera Detects Face
   ↓
Is Face Recognized?
   ↓ Yes                    ↓ No
Unlock Door          Send Alert + Capture Photo
   ↓                        ↓
Send Data to App      Wait for Owner's Response
   ↓
Auto Lock After Delay

🔌 Part 3 – Circuit Diagram, Wiring & Hardware Connections

In this part, we will understand how to connect all the components of the AI + IoT Smart Door Lock System properly. सही wiring करना बहुत जरूरी है क्योंकि गलत connections से ESP32 खराब हो सकता है या camera और relay काम नहीं करेंगे।

🖇️ 🔹 Hardware Connection Overview

We are using:

ESP32-CAM (for Face Recognition)
ESP32 / NodeMCU ESP32 Dev Board (optional if using Blynk or Google Assistant control)
Servo Motor / Relay + Solenoid Lock (for locking system)
5V Power Supply (for stable operation)

🧠 1. ESP32-CAM Power & Serial Wiring

ESP32-CAM Pin	Connection
5V / VCC	5V Power Supply
GND	Power Supply GND
U0R (RX)	ESP32 / USB to TTL TX pin
U0T (TX)	ESP32 / USB to TTL RX pin
GPIO 0	GND (only while uploading code)
3.3V Output	Can be used to power small sensors (optional)

✔ Upload करते समय GPIO0 को GND से connect करें
✔ Code upload होने के बाद GPIO0 को हटाएँ और reset करें

🔐 2. Servo Motor / Solenoid Lock Wiring

📌 If using Servo Motor (SG90 / MG995):

Servo Wire	Connect To
Red	5V Power Supply
Brown / Black (GND)	GND of ESP32
Orange / Yellow (Signal)	GPIO 12 (or 13/15) of ESP32-CAM

📌 If using Relay + Electronic Lock:

Relay Module Pin	Connect To
VCC	5V
GND	GND
IN	GPIO 14 (or any digital pin on ESP32-CAM)
NO (Normally Open)	One wire of lock
COM (Common)	Power source for lock (12V/5V depending on lock)

📡 3. ESP32 / Blynk / IoT Control Board (Optional but Recommended)

If you want Google Assistant, Alexa, Mobile App control, then add an ESP32 Dev Board separately.

ESP32 Dev Board	Connection
VIN (5V)	5V Adapter
GND	Common Ground
TX / RX	For communication with ESP32-CAM (optional for inter-board UART)
GPIO Pin (D5/D12)	Connected to Relay IN or Servo signal
3.3V	Used to power logic devices or sensors

⚡ 4. Power Supply Guide (Very Important)

Component	Voltage	Current Required
ESP32-CAM	5V	500mA
ESP32 Dev Board	5V	300mA
Servo Motor	5V	500mA to 1A
Solenoid Lock	5V or 12V	1A to 2A
Relay Module	5V	70mA

⚠️ Important Note:

ESP32 का 5V pin directly high-load devices जैसे servo & lock को power न दे
Use separate 5V 2A adapter or 12V + Buck Converter
All grounds (GND) must be connected together (common ground)

🖼️ Circuit Diagram (Explanation)

You can create this using tools like Fritzing / Proteus / Tinkercad, but the connections are clearly explained above.

Circuit Highlights:
✅ ESP32-CAM → Camera + Wi-Fi + AI Face Detection
✅ Servo/Relay → Locking Mechanism Control
✅ Power Supply → Stable 5V/12V Source
✅ ESP32 Dev Board → IoT + App + Voice Assistant Control

✅ Part 4 (Continue) – Detailed Code Explanation Line-by-Line

अब हम ऊपर दिए गए ESP32 Main Board कोड को आसान भाषा में step-by-step समझेंगे ताकि आप या आपका viewer इसे कॉपी ही नहीं बल्कि properly समझकर implement भी कर सके।

📌 1. Header Files & Template Configuration

#define BLYNK_TEMPLATE_ID "Your_Template_ID"
#define BLYNK_AUTH_TOKEN "Your_Blynk_Token"
#define BLYNK_PRINT Serial

#include <WiFi.h>
#include <WiFiClient.h>
#include <BlynkSimpleEsp32.h>
#include <ESP32Servo.h>
#include <WebServer.h>

🔹 What this means?

BLYNK_TEMPLATE_ID → Blynk App में बनाया गया Template ID
BLYNK_AUTH_TOKEN → Blynk से Email पर भेजा गया token
WiFi.h और WiFiClient.h → ESP32 को Wi-Fi से connect करने के लिए
ESP32Servo.h → Door Lock Servo को control करने के लिए
WebServer.h → ESP32 को web server बनाने के लिए (face recognition से unlock request receive करने के लिए)

📌 2. Wi-Fi Credentials & Hardware Pins

char ssid[] = "Your_WiFi_Name";
char pass[] = "Your_WiFi_Password";

Servo lockServo;
int servoPin = 12;  
int relayPin = 14;  
WebServer server(80);

✔ ssid और pass = Wi-Fi connection के लिए
✔ servoPin 12 = Motor जो लॉक को घुमाएगा
✔ relayPin 14 = अगर आप solenoid lock या magnetic lock use कर रहे हैं
✔ server(80) → ESP32 को HTTP requests सुनने के लिए port 80 पर ready रखता है

📌 3. Setup Function – Start Everything Here

void setup() {
  Serial.begin(115200);
  WiFi.begin(ssid, pass);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("\nConnected to Wi-Fi!");
  Blynk.begin(BLYNK_AUTH_TOKEN, ssid, pass);

  lockServo.attach(servoPin);
  pinMode(relayPin, OUTPUT);
  lockServo.write(0); // Default Locked Position

  server.on("/unlock", []() {
    unlockDoor();
    server.send(200, "text/plain", "Door Unlocked");
  });

  server.begin();
}

🔹 Explaination:

Function	Purpose
`Serial.begin()`	Debugging messages
`WiFi.begin()`	Connect ESP32 to internet
`Blynk.begin()`	Connect ESP32 with Blynk Cloud
`lockServo.attach()`	Initialize Servo Motor
`server.on("/unlock")`	जब भी browser या ESP32-CAM इस URL को hit करेगा → Door unlock होगा

Example:
If you visit → http://192.168.1.50/unlock → Door will open automatically.

📌 4. Unlock Function

void unlockDoor() {
  Serial.println("Unlocking Door...");
  digitalWrite(relayPin, HIGH);
  lockServo.write(90);
  delay(3000);
  digitalWrite(relayPin, LOW);
  lockServo.write(0); // Lock again
}

✔ Servo rotates 0° → 90° to open lock
✔ Relay gives power to solenoid lock
✔ 3 seconds delay = Enough to open the door
✔ Then automatically locks again for safety

📌 5. Blynk Voice/Manual Control Button

BLYNK_WRITE(V0) {
  unlockDoor();
}

✔ जब भी आप Blynk App में बटन दबाएंगे → ये function call होगा
✔ Google Assistant + Blynk भी इसी pin V0 को trigger करेगा

📌 6. Main Loop Function

void loop() {
  Blynk.run();
  server.handleClient();
}

✔ Blynk.run() = Real-time connection to mobile app
✔ server.handleClient() = Handle face recognition unlock request from ESP32-CAM

✅ ✅ Part 4 में अब तक क्या पूरा हुआ?

✔ ESP32-CAM + ESP32 कोड पूरा
✔ WebServer + IoT + Servo Lock + Relay Control
✔ Line-by-line explanation
✔ 100% working concept for YouTube/Blog/Project

✅ 📍 Part 5: Complete ESP32 Code + Sensor Logic + Blynk Integration

🛠️ 5.1 Required Libraries (Add in Arduino IDE):

Arduino IDE में यह Libraries जरूर Install करें:

Library Name	Install From
Blynk by Volodymyr Shymanskyy	Library Manager
ESP32 Board Package	Board Manager
SimpleTimer (auto included with Blynk)	Comes with Blynk

✅ 5.2 Complete Arduino Code (With Comments)

#define BLYNK_TEMPLATE_ID "YOUR_TEMPLATE_ID"
#define BLYNK_DEVICE_NAME "Water Level System"
#define BLYNK_AUTH_TOKEN "YOUR_AUTH_TOKEN"

#include <WiFi.h>
#include <WiFiClient.h>
#include <BlynkSimpleEsp32.h>

#define TRIG_PIN  13  // D13 → Trig Pin
#define ECHO_PIN  12  // D12 → Echo Pin
#define RELAY_PIN 14  // Motor Control (Optional)

char auth[] = "YOUR_AUTH_TOKEN";   // Blynk Auth Token
char ssid[] = "YOUR_WIFI_NAME";    // WiFi Name
char pass[] = "YOUR_WIFI_PASSWORD"; // WiFi Password

long duration;
int distance;
int tankHeight = 30;  // Tank Height in cm
int waterLevel;

BlynkTimer timer;

// Function to get distance from ultrasonic sensor
int getWaterLevel() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  duration = pulseIn(ECHO_PIN, HIGH);
  distance = duration * 0.034 / 2;  // Convert to cm

  waterLevel = map(distance, 0, tankHeight, 100, 0);
  if (waterLevel > 100) waterLevel = 100;
  if (waterLevel < 0)   waterLevel = 0;

  return waterLevel;
}

// Send data to Blynk app
void sendData() {
  int level = getWaterLevel();
  Blynk.virtualWrite(V1, level);  // Gauge
  Blynk.virtualWrite(V4, level);  // Graph

  if (level >= 90) {
    Blynk.virtualWrite(V2, "Tank Full");
    Blynk.virtualWrite(V3, 255); // Red LED
    digitalWrite(RELAY_PIN, LOW);  // Auto Motor Off
  }
  else if (level <= 10) {
    Blynk.virtualWrite(V2, "Tank Empty");
    Blynk.virtualWrite(V3, 255);
  }
  else {
    Blynk.virtualWrite(V2, "Normal");
    Blynk.virtualWrite(V3, 0);
  }
}

void setup() {
  Serial.begin(115200);

  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(RELAY_PIN, OUTPUT);
  digitalWrite(RELAY_PIN, HIGH); // Motor initially Off

  Blynk.begin(auth, ssid, pass);
  timer.setInterval(2000L, sendData); // Send data every 2 seconds
}

void loop() {
  Blynk.run();
  timer.run();
}

✅ 5.3 Code कैसे काम करता है? (Simple Explanation)

Step	Description
1	Trig Pin से Sound Wave भेजी जाती है
2	Echo Pin से Reflection Time Measure होता है
3	Formula से Distance निकाला जाता है (cm में)
4	Distance को Tank Height के हिसाब से Water % में Convert किया जाता है
5	Blynk App → Gauge, Label, Graph पर Data भेजते हैं
6	अगर पानी 90%+ है → Motor को Auto OFF & Alert
7	अगर पानी 10% से कम है → Low Level Alert

✅ 5.4 Output क्या दिखेगा?

✔ Mobile App पर Real-Time Percentage
✔ Status Text → “Tank Full / Normal / Empty”
✔ LED Widget रंग बदलेगा Alert के समय
✔ Graph पर Live Data Update
✔ (Optional) Relay से Motor ON/OFF Auto Control

🎯 Part 5 Complete!

अब अगले Part 6 में हम Blynk App Dashboard, Widgets Setup (Gauge, Graph, LED) properly डिज़ाइन करेंगे।

✅ Part 6: Blynk IoT App Setup & Dashboard Design

In this section, we will set up the Blynk IoT mobile app and web dashboard to monitor the water level, view notifications, and control the water pump remotely.

📱 6.1 Create a New Project in Blynk IoT (Mobile App)

Open the Blynk IoT App (Android / iOS).
Tap on “+ New Device” → “Create Device”
Select:
- Template Name: Smart Water Level Monitoring
- Hardware: ESP32
- Connection Type: Wi-Fi
Blynk will automatically generate:
✅ Template ID
✅ Device Name
✅ Auth Token → Copy and paste it into your ESP32 code.

📊 6.2 Add Widgets in Blynk App

Widget Name	Purpose	Virtual Pin
Gauge	Displays % water level	V1
Label	Shows status (Full/Low/Normal)	V2
LED	Alert Indicator	V3
SuperChart (Graph)	Real-time water level graph	V4
Button (Optional)	Manual pump on/off control	V5
Notification	Sends alert pop-ups	Auto

🛠 How to Configure Widgets:

✅ 1. Gauge Widget

Name: Water Level
Pin: V1
Range: 0 to 100
Unit: %

✅ 2. Label Widget

Name: Status
Pin: V2
Value Display: Tank Full / Empty / Normal

✅ 3. LED Widget

Name: Alert LED
Pin: V3
Color Mode: Auto

✅ 4. SuperChart (Graph Widget)

Add a Data Stream:
- Name: WaterLevel
- Pin: V4
- Type: Percentage (%)
- Update Interval: 1s or 5s

✅ 5. Button Widget (Optional for Motor Control)

Name: Motor Switch
Mode: Switch
Pin: V5
If using relay with ESP32: handle in code with BLYNK_WRITE(V5)

🌐 6.3 Blynk Web Dashboard Setup (Optional but Professional)

Visit: https://blynk.cloud
Log in using the same account
Go to: My Devices → Your Device → Dashboard
Add widgets (Gauge, Chart, Switch, Indicators)
Link same Virtual Pins: V1, V2, V3, V4, V5
Save and view real-time water level on browser

📩 6.4 Enable Alerts & Notification System

✅ For Tank Full or Empty Alerts:

Go to Event → Add New Event
- Name: Tank_Full
- Condition: When V2 = “Tank Full”
Enable → Send Push Notification or Send Email

✅ 6.5 Final Output of Blynk App

✔ Real-time water percentage on gauge
✔ Tank full / empty alerts on phone
✔ Live water-level graph over time
✔ Pump control from mobile or automatically
✔ Notification when water is low or overflows

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